The second type is the sessions where we spoke to customers in shorter but multiple sessions over a period of months. In these types of sessions we had a conversation with customers, went and made something, showed it to them and had a conversation around what we made. They shared their thoughts with us and we then went back, changed things and went back for a conversation again.
I found out that the second approach produces products of much better quality. The number of feedback loops is directly to proportional to the quality of the innovation and the amount of value a product brings to a customer. Product managers can control and fine tune the number of conversations, duration of each conversation and the frequency of these conversations to suit the needs of the team. This is an art that @esdediego has mastered and will share with the world soon.
I highly recommend increasing the number of times you have customer conversations. It is the key to success for you and for your customer.